My 1yr old started on whole milk and she loved it, and per day she has more than 21oz, i've read that too much whole milk can cause anemia, is this true?

It is possible...: For a 1 year old, you want them to drink around 16-24 oz of whole milk per a day. As long as they are interested in eating solid foods too, that amount is ok. If they seem to only want milk, scale back to 16 oz only. Increase iron-rich foods in your child's diet, like meat, poultry, fish, beans, and iron-fortified foods (cereal, for example). Iron deficiency happens when kids drink just milk.